wrong Column size

I use this code to get the column sizes from printView() function:
for (var i=0; i<col_length; i++){
if (this._hrrar && this._hrrar[i]) continue;
var hcell=this.hdr.rows[1].cells[this.hdr.rows[1]._childIndexes?this.hdr.rows[1]._childIndexes[parseInt(i)]:i];
var colspan=(hcell.colSpan||1);
var rowspan=(hcell.rowSpan||1);
//console.log(i,colspan, rowspan);
for (var j=1; j<colspan; j++)
html += ‘


Is it possible to get the size from the column in pixel and not in prercent?
You can see I made some console.log because the percent of the last column is wrong.
In my example the last column get 12%, but it have the same size (width=75) then the column before that have 5%. So one column get 5% and the second (last) 12% with the same size in pixel?

Please help